Chemical modification of fibrous cellulose with sodium n-methylbis(2-sulfatoethyl)amine and with n-methylbis(2-chloroethyl)amine to impart crease resistance in fabrics

ABSTRACT

N-methylbis(2-sulfatoethyl)amine and the monosodium salt of this new compound have been prepared and applied to cotton to impart crease-resistant characteristics to the fabrics. N-methylbis(2chloroethyl)amine, a related known compound, was also reacted with the fibrous cellulose. Respectively, a pad-cure process was employed on the one and a pad wet-cure process was employed on the other to produce cross-linked cellulosic derivatives.

United States Patent Roberts et al.

[ Mar. 7, 1972 of New Orleans; Mary Ann F. Brannan, Metairie, all of La.

[73] Assignee: The United States of Americaas represented by the Secretary of Agriculture [221 Filed: Feb. 17,1971

211 Appl.No.: 116,283

[52] US. Cl ..8/l16.2, 8/120, 260/563, 260/231 R, 260/231 A [51] Int. Cl .Q ..D06m 13/36, D06m 13/38 [58] Field of Search ..8/116.2, 120

[56] References Cited UNlTED STATES PATENTS 2,459,222 1/1949 Guthrie ..8/1 16.2 1,777,970 10/1930 Hartmann ..8/1 16.2

Primary Examiner-George F. Lesmes Assistant Examiner-J. Cannon Attorney-R. Hoffman and W. Bier [57] ABSTRACT N-methylbis( 2-sulfatoethyl)amine and the monosodium salt of this new compound have been prepared and applied to cotton to impart crease-resistant characteristics to the fabrics. N- methylbis(2-chloroethyl)amine, a related known compound, was also reacted with the fibrous cellulose. Respectively, a pad-cure process was employed on the one and a pad wet-cure process was employed on the other to produce cross-linked cellulosic derivatives.

6 Claims, No Drawings CHEMICAL MODIFICATION OF FIBROUS CELLULOSE WITH SODIUM N-METHYLBIS(2- SULFATOETHYIJAMINE AND WITH N-METHYLBIS(2- CHLOROETHYL)AMINE TO IMPART CREASE RESISTANCE IN FABRICS A nonexclusive, irrevocable, royalty-free license in the invention herein described throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to N-methylbis( 2-sulfatoethyl)amine, the monosodium salt thereof, and to the preparation of these two new compounds. This invention also relates to the crosslinking of fibrous cellulosic textiles with these new compounds, and to a process for reacting the related but known N- methylbis(2-chlorethyl)amine. In applying these compounds to cotton fabric a cure at elevated temperature is preferred in one instance while a cure at room temperature is preferred in the other case to produce thecellulosic derivatives in the form of chemically cross linked fabrics.

The main object of this invention is to provide new reactive cross-linking agents which are useful in chemical modification of cellulose, primarily in the form of textiles.

A second object of this invention is to provide a method for the preparation of the compounds of the main object.

A third object of this invention is to provide cross linked products whose linkages between cellulose and reagent residues are more stable to acid and to base than those of conventional finishing agents for cotton fabrics.

A fourth object is to provide cross linked cottons which do not tender or dissolve on treatment with hypochlorite bleach or in a subsequent ironing.

It is well known that wrinkle-resistant finishes for cellulosic fabrics are based on covalently bonded cross-links joining the cellulose molecules within the fibers. The establishment of cross-links binds the fibers together in the configuration of the fabric at the time of cross-linking. Those skilled in the art know that cellulose in the form of fibers can be reacted with a variety of compounds containing functional groups to produce cellulose derivatives having these groups attached to the cellulose by covalent bonds. Among the types of functional groups which can react with cellulose are the following: carboxylic acids and derivatives of carboxylic acids, such as acyl halids, and anhydrides, alkyl halides, sulfates and other alkylating agents; organic epoxides; N-methylol amides, N-methylol amines, N-methylol carbamates, and other N-methylol compounds; compounds containing activated double bonds such as vinyl sulfones and acrylic acid derivatives; and other compounds containing functional groups capable of reacting with organic hydroxyl groups. lt is also well known that compounds containing two such functional groups, which may be the same or different, and which are both capable of reacting with cellulose, can develop covalent cross-links in cellulose.

Esters of cellulose, which are formed by the reaction of carboxylic acids, acyl chlorides and anhydrides with cellulose, and acetals, which result from the reaction of cellulose with the N-methylol derivatives, are acid and base labile and are subject to removal by alkaline detergents or acid souring during laundering; however, cellulose ethers are stable under both acidic and basic conditions and from the standpoint of stability to changes in pH are superior to esters and acetals.

We have discovered a new bifunctional reagent, N-methylbis(2-sulfatoethyl)amine, useful for forming cross-links in cellulosic materials by ether formation, and further, we have discovered that the already known N-methylbis( 2- chlorethyl)amine is also capable of forming ether cross-links in cellulosic materials.

Substantially any cellulosic material can suitably be employed in the present process. lllustrative examples of such materials include cellulose from cotton, flax, ramie, wood, regenerated cellulose, partially substituted celluloses such as cyanoethylatcd cellulose, and the like. In general, the cellulosic textile fibers in the form of free fibers, slivers, yarns, threads, or fabrics are preferred starting materials.

N-methylbis(2-sulfatoethyl)amine is prepared by combining reagents in the approximate ratio of I mole of N-methylbis(2-hydroxyethyl)amine and 2 moles of chlorosulfonic acid directly or in suitable nonaqueous solvents. The reaction may be carried out at room temperature or, preferably, at a temperature sufficiently below room temperature such that the rate of the reaction and the exotherm can be controlled. After the reaction is complete, sufficient base is added to form the monoor disalt of the N-methylbis(2-sulfatoethyl)amine. The compound may be used directly to prepare solutions for reaction with cotton fabric or the monoor disalt may be purified by crystallization from aqueous ethanol.

For reaction with cotton, pad bath solutions are prepared containing up to 35 percent N-methylbis(2- sulfatoethyl)amine or its monoor disalt; the same solution may contain up to 35 percent base (NaOH, KOH, or other strong base). The fabric to be treated is soaked in the solution for a period up to 30 minutes or even longer at temperatures up to 50 C. The excess solution is removed from the fabric so that the wet pickup may reach up to 225 percent. The impregnated fabric is then heated in an oven at a suitable temperature up to 230 for a suitable period of time, but preferably l60 C. for the necessary length of time up to 20 minutes to promote reaction. The fabric is then washed free of unreacted reagents and byproducts of the reaction and line dried. The fabric may be given multiple treatments (e.g., 4 or 5 treatments) to increase the add-on.

Thereaction of N-methylbis(2-sulfatoethyl)amine with cotton may be conducted by applying it to cotton from a pad bath of the reagent in the form of the monoor disalt. The wet pickup may reach 150 percent. The cotton still wet with this reagent or after drying is padded through a solution of strong base for an additional wet pickup up to 150 percent. This impregnated fabric may be cured, with or without previous drying at temperatures up to 230 C. The order of padding the cotton fabric may be reversed so that it is first immersed in the alkali solution and later immersed in the reagent solution. The fabric is washed as indicated above.

The N-methylbis(2-haloethyl)amine may be in the form of the chloride, bromide, or iodide. For reaction with cotton, the fabric is impregnated with a solution containing up to 50 percent of the halo compound in the form of its acid salt. The excess solution is squeezed from the fabric to a wet pickup of up to 200 percent. The impregnated fabric may then be immersed in a solution of base (NaOH, KOH, etc.) of sufiicient concentration to be at least stoichimetrically equivalent to the halogen contained in the fabric or up to a 50 percent concentration for as long as 2 hours at temperatures ranging from 20 to C. Instead of the above procedure the impregnated fabric may be padded through a solution containing up to 50 percent base (NaOH, KOH, etc.) and stored in a moistureproof container for up to 16 hours at temperatures ranging from 20 C. to C. The reverse order of padding may also be used. The reacted fabric is washed free of excess reagents and byproducts and line-dried. The fabric may be subjected to multiple treatments in the same manner in order to obtain higher add-ons.

EXAMPLE 1 N-methylbis(2-hydroxyethyl)amine l 19 g. (1 mole) was dissolved in 357 g. of chloroform in a two-necked flask equipped with a stirrer and reflux condenser and cooled to 0 C. To this solution was slowly added from a dropping funnel 233 g. (2 moles) of chlorosulfonic acid dissolved in 700 g. of chloroform. After all of the chlorosulfonic acid was added the mixture was removed from the cooling bath and stirred until the contents warmed to room temperature. The chloroform was removed by evaporation under vacuum. The crude disulfato compound was dissolved in 500 ml. of water and neutralized to pH 7 with 10 percent sodium hydroxide. The solution was concentrated under vacuum, almost to dryness. The residue was then dissolved in the minimum amount of 65 percent ethanol and upon cooling crystallized yielding 250 g. (78.5 percent of theory) of the monosodium N-methylbis(2- sulfatoethyl)amine monohydrate.

Analysis: Calculated percent for C H S O NNa: N=4.38, S=20.06;

found: N=4.23, S=20.34.

EXAMPLE 2 An 8 10-in. swatch of 80x80 printcloth was soaked for 5 minutes in a solution composed of 20 g. of sodium N-methylbis(2-sulfatoethyl)amine monohydrate, 10 g. of sodium hydroxide, and 70 g. of water. The soaked sample of fabric was passed through squeeze rolls to obtain a wet pickup of 200 percent. The sample was cured for minutes at 130 C. in a forced-draft oven, rinsed thoroughly in flowing tapwater, and air-dried. The nitrogen content of this sample was 0.43 percent, which corresponds to a D8 of 0.052.

To determine whether cross-linking had taken place in this reaction, the treated sample was submitted to a standard test with cupriethylenediamine hydroxide (cuene). The treated sample was found to be thoroughly cross linked. The cupriethylenediamine hydroxide test is performed as follows to determine if a previously untreated cellulosic fiber has reacted with a potential cross-linking compound. A few fibers of the treated sample are placed on the table ofa microscope, a drop of freshly prepared 0.5 M cupriethylenediamine hydroxide is added to the fibers, and a period of about to minutes of time is permitted to elapse, to allow for swelling and potential dissolution. 1f the fibers are found to be soluble no cross-linking has occurred. If, on the other hand, there is little or no dissolution noted this is an indication that crosslinking has occurred.

In reference to wrinkle recovery values the tests gave these results (warp plus filling angles):

Conditioned Wet Treated Sample 218 263 Untreated Control 191 177 Portions of the treated sample were submitted to second and third treatments with the same solution obtaining the following results:

Conditioned Wet Second (N, 0.66%; DS 0.080) 218 270 Third (N. 092%; DS 0.11) 225 264 The nitrogen content of the treated cotton was not changed following treatments with 0.05 N hydrochloric acid, 0.1N acetic acid, and 1N sodium hydroxide. The fabrics did not discolor or tender on being bleached with hypochlorite, dried, and ironed.

EXAMPLE 3 The process of Example 2 was employed again but with the exception that the solution was composed of 20 g. of sodium N-methylbis(2-sulfatoethyl)amine monohydrate, 24 g. of sodium hydroxide and 56 g. of water. The treated fabric had a nitrogen content of 0.26 percent, which corresponds to a D8 of 0.03. This sample was determined tobe cross linked, by the method of Example 2. The wrinkle recovery values obtained were these:

Conditioned W'et Treated Sample 202 265 Untreated Control 191 177 Portions of the treated sample were submitted to second and third treatments with the same solution, obtaining the following results:

Third (N,U.66%; 0511.030 [73'' ExAMl LE 4 An 8X 1 6-in. swatch of 80 printcloth weighing 7.7 g. was treated with two dips and two nips in a 19.25 percent w/w solution of N-methylbis(2chloroethyl)amine hydrochloride. The wet pickup was 120 percent. The wet impregnated fabric was then immersed in ml, of 7.3 percent sodium hydroxide solution at 25 C. for 45 minutes with occasional agitation. The fabric was then washed with flowing tapwater and air dried. The nitrogen content of the treated sample was 0.29 percent, which corresponds to a D8 of 0.034. This sample was determined to be cross linked, by the method of Example 2.

The wrinkle recovery values obtained were these:

Tear Conditioned Wet Strength Treated Sample 220 226 440 g. Untreated Control 191 171 1.100 g.

Portions of the treated sample were submitted to a second, a third, and a fourth treatment with the same solution, obtaining the following results:

Tear Conditioned Wet Strength Second (N, 0.45%; DS 0.053) 233 255 330 g. Third (N, 0.59%; 05 0.071) 253 276 270 g. Fourth (N,0.91%;DS 0.10) 247 281' 240 g.

EXAMPLE 5 An 8X16-in. swatch of 80x80 printcloth weighing 7.7 g. was treated with two dips and two nips in a 7.3 percent sodium hydroxide solution. The wet pickup was 1 15 percent. The wet impregnated fabric was then immersed in 100 ml. of 19.25 percent w/w solution of N-methy1bis(2-ch1oroethy1)amine hydrochloride at 25 C. for 45 minutes with occasional agitation. The fabric was then washed with flowing tapwater and air-dried. The nitrogen content of the treated sample was 0.71 percent, which corresponds to a D5 of 0.085. This sample was determined to be cross linked by the method of Example 2.

We claim:

1. A process for imparting crease-resistant characteristics to cotton and other cellulosic fabrics comprising:

a. impregnating a cellulosic fabric with a solution containing N-methy1bis(2-sulfatoethyl)amine or the monoor disalt thereof,

b. reacting the impregnated fabric by curing, and

c. washing the reacted fabric free of unreacted chemicals- 2. A process for imparting crease-resistant characteristics to cotton and other cellulosic fabrics, comprising:

a. impregnating a cellulosic fabric with a solution of N- methylbis( 2-chlor0ethy1)amine hydrochloride,

b. immersing the impregnated fabric of (a) in a solution of strong base, maintaining the fabric immersed in this solution at a temperature up to 100 C. for a length of time up to 2 hours, to obtain a reacted cellulosic fabric.

3. A process for imparting crease-resistant characteristics to cotton and other cellulosic fabrics, comprising:

a. impregnating the cellulosic fabric with a solution of sodium hydroxide,

b. immersing the impregnated fabric of(a) in an aqueous N- methylbis(2-chloroethyl)amine solution, and maintaining the fabric immersed in this solution at a temperature not exceeding 100 C. to obtain a reacted cellulosic fabric.

4. The cellulosic derivative prepared by the process of claim 5. The cellulosic derivative prepared by the process of claim 6. The product produced by the process of claim 3. 

2. A process for imparting crease-resistant characteristics to cotton and other cellulosic fabrics, comprising: a. impregnating a cellulosic fabric with a solution of N-methylbis(2-chloroethyl)amine hydrochloride, b. immersing the impregnated fabric of (a) in a solution of strong base, maintaining the fabric immersed in this solution at a temperature up to 100* C. for a length of time up to 2 hours, to obtain a reacted cellulosic fabric.
 3. A process for imparting crease-resistant characteristics to cotton and other cellulosic fabrics, comprising: a. impregnating the cellulosic fabric with a solution of sodium hydroxide, b. immersing the impregnated fabric of (a) in an aqueous N-methylbis(2-chloroethyl)amine solution, and maintaining the fabric immersed in this solution at a temperature not exceeding 100* C. to obtain a reacted cellulosic fabric.
 4. The cellulosic derivative prepared by the process of claim
 1. 5. The cellulosic derivative prepared by the process of claim
 2. 6. The product produced by the process of claim
 3. 